Here is a nice and neat feature to surface some document properties that usually live in the Document information panel:
Quick Parts. For those of you raising an eyebrow (whaa?) , here’s a primer :
The feature is not new and quite useful especially in the newer versions of Office where, to get to the SharePoint Document Properties, you need to go through File information.
Now if you are asking yourself where is this information stored, like in all the Office modern documents, the information is committed in the document itself (see here why and how) at the time when the document is uploaded/downloaded through a feature called promotion/demotion.
As you would expect, we store the items in the document itself based on the field references and these are GUIDs ( they are based on the field definition , that means the field ID in the list itself and the SourceId for the field, which can be a reference to a managed metadata field, the web etc.)
Now one question that pops into mind is : will the Quick Part update itself if I copy the document into another site collection?
The answer is… sometimes.
It will update if the IDs are the same (see here why the web Id can be the same or different).If the referenced ids are different, you will have to remove the Quick Part and re-add it after copy in order to re-establish the correct relationship.
Hope this helps clarifying some questions.